Walking aids include walking sticks, canes, crutches and the like which are used by individuals to assist in supporting them by taking some of the weight which would otherwise be borne by the feet alone. The walking aid is usually held in the hand in the case of a walking stick or cane, on the arm in the case of certain forms of crutch and underneath the arm in the case of other types. In all of these cases, an important desideratum is that the engagement between the base of the walking aid and the ground surface is adequate to prevent slipping. This may be achieved, for example, by a very small ground-engaging surface such as a spike or narrow ferrule, but this is not ideal, particularly if the walking aid is to be used indoors where such a small surface, because of the high pressure it generates, may cause damage to floors, carpets or the like.
An alternative approach is to have a high friction surface, larger area pad; rubbery end caps which fit over walking sticks and the like are well known. There are several commercially available designs, none of which is ideally suited to all conditions and many of which are inflexible insofar as the degree of grip they give depends very strongly on the angle between the support surface and the longitudinal axis of the cane or stick itself. EP-A-0605935 discloses a crutch tip incorporating two different materials with a view to improving the grip, but this will only operate properly when the crutch shaft is vertical.
A number of suggestions have been made in the patent literature to avoid this difficulty by enabling the end to swivel. Examples of such disclosures are EP-A-0112141, FR-A-2715559 and U.S. Pat. No. 5,865,204.
The greater the resistance of the foot slipping, so the greater the resistance of the cane to twisting, i.e. rotation about its elongate axis. This can make for discomfort in use, and accordingly it is known to provide, between the ground-engaging member and the stick or cane itself, a degree of rotational freedom.
A separate issue, of particular importance in the case of crutches but nevertheless also in the case of walking sticks, is the relative axial incompressibility of the stick itself. There have been a number of suggestions in the patent literature to provide walking aids with resilient feet, i.e. ones which are resiliently mounted on the shaft of the walking aid itself. These normally take the form of some type of telescoping arrangement with an internal spring. Examples of these are disclosed in GB-A-124691, WO 00-10502, U.S. Pat. No. 2,888,022, U.S. Pat. No. 2,856,943, U.S. Pat. No. 2,397,499, GB-A-613046, DE-U-8751507 and U.S. Pat. No. 2004/0035453.
DE-C-4136210 discloses an alternative approach to providing resilience in a crutch. It has a telescoping section with a cellular polyurethane elastomer cylindrical member as a shock absorber. U.S. Pat. No. 4,881,564 discloses a crutch tip with a deformable skirt and including a damping pad.
Many of the constructions disclosed in the various patent publications identified above are complex and susceptible in particular to failure in use on account of wear and tear, or the penetration of dust and grit into moving parts.